Mountain birds will die out as planet warms

貴州貴陽市北師大貴陽附中 羅躍梅

一份新的研究表明，由于受到氣候變化的影響，山地鳥正在離開它們生活的自然環(huán)境，并逐漸走向滅絕。

Scientists have recreated a 1985 study of birds in Peru that shows climate change is pushing them from their natural environment.

Thirty years ago， researchers studied more than 400 kinds of birdsliving on a mountainsidein Peru. In 2017， researchers looked again atthe bird populations. They found that almost all hadmoved to higher placesin the mountain.Almost all haddecreased in size. And， the scientists say at least eight bird groups that started at the higher elevations (海拔) haddied outcompletely.

John W. Fitzpatrick is director of the Cornell Laboratory of Ornithology （鳥類學(xué)） and a co-writer of the study. He said， “Once you move up as far as you can go，there's nowhere else left.”

The researchers say the birds might havemoved up the mountainbecause of temperature changes. Or， they say changes to food sources may have forced them to go higher. The findings were published in theProceedings of the National Academy of Sciences. Past research has documented birds and other animals moving up in elevation in reaction to warming temperatures.

Mark Urban is director of the Center of Biological Risk at the University of Connecticut.He said this recent study was the first to prove that rising temperatures and moving to avoid them canlead to extinction.

In 1985， Fitzpatrick and a team of scientists established a camp alongside a river running down a mountainside in southeastern Peru.He wanted to document where tropical bird groups there lived. His team spent several weeks using nets to catch and release birds. They kept detailed notes of birds they caught， saw or heard. In 2016， Fitzpatrick passed his notes，photos and other records to Benjamin Freeman.He is with the Biodiversity Research Centre at the University of British Columbia. Freeman has been researching tropical birds for more than 10 years. He set out in August and September of 2017 to copy Fitzpatrick's study. His team used the same methods， searching the same places in the same time of year. Freeman's team wanted to see how things had changed for the bird groups since 1985.The average temperatureson the mountain had risen 0.42 ℃. Freeman's team placed 20 sound recording devices on the mountain to record the sounds of birds that might not easily be seen. Freeman said that the birdsmoved an average of98metersfurther up the mountain. He said he believes that temperature isthe main cause of the birds'movement.

Fitzpatrick noted that birds used to living in areas with little temperature change may be especiallyat risk because of climate change.

He said， “We should expect that what's happening on this mountain top is happening more generally in the Andes， and other tropical mountain ranges.”

Reading Check

1.What leads to mountain birds' dying out according to the text？

A.The planet warming.

B.Lack of water.

C.Human's hunting.

D.Tree cutting.

2.When did Freeman set out to copy Fitzpatrick's study？

A.In 1985.

B.In 2017.

C.In 2018.

D.In 2016.

Language Study

話題表達(dá)語言整理

1.live on a mountainside 住在山坡上

2.the bird populations 鳥類的數(shù)量

3.move to higher places 遷徙到更高的地方

4.decrease in size 規(guī)模減小

5.die out 滅絕

6.move up the mountain 向山上遷徙

7.lead to extinction 導(dǎo)致滅絕

8.the average temperatures 平均氣溫

9.move an average of 98 meters 平均遷徙98米（高）

10.the main cause of the birds' movement 鳥類遷徙的主要原因

11.（be）at risk because of climate change 由于氣候變化而面臨風(fēng)險